I think in that case its a few factors, but the most important is the approach the child takes, and the instructor has a lot of influence on thats.
Generally teachers arent too flexible, they suggest a very specific style, and that style is heavy on memorization. This also tends to fail for intelligence. Intelligence requires a level of curiosity and a determination to observe how you learn best and adjust it to your strengths. So either a child needs to learn this for themselves (which is hard when instructors penalize them for this most of the time) or they have to have an unusually adept instructor who knows better.
Isnt everything when it comes to education discovery, either of information/understanding of a topic or of yoursef?
Yes I agree, sadly fewer great teachers has this consequence. Though to be fair a person can still spark it on their own (though this isnt as effective as in person) through youtube or other mediums that can make the subject matter interesting without focusing on just the learning.
I'd be curious to find out the impact of /how/ someone is taught to learn on the outcome of their ability to learn quickly. Or /how/ someone is improperly taught to learn reduces their ability to learn new things in other domains. Such as those poorly instructed in arithmetic, are they more likely to struggle with learning semantic structures of languages? Maybe. That's not an illogical leap.
What if it really came down to the instructor lottery, and those who are considered "good learners" are simply those who were instructed well enough early on to develop highly functional concept absorption?
If that were accepted as true. Teachers unions would be a thing of the past, and quickly.